Igor Morozov

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• Ph.D. in Plasma Physics
• Research Fellow at Macquarie University

The study considers a possibility of studying the manifestation of the major background ions derived from the main elements (H, N, O, and Ar) of inductively coupled plasma under low-temperature ("cold") plasma conditions through thermodynamic simulation. These ions, known to induce significant spectral interferences, are always observed when aqueou...

In this work, we prepare a simulation framework for a high-accuracy numerical study of electron-ion temperature relaxation in nonideal (strongly coupled) plasmas. The existing relaxation rate theories require either parameter selection or some pre-knowledge of the electron-ion correlation functions and effective interaction potentials. This makes n...

Argon compounds play an important role in the mass spectrometry with inductively coupled plasma and other applications. At the same time, there is a little knowledge of their electronic terms and thermodynamic functions due to the complexity of experimental observations. In this work, the ab initio simulations are performed to obtain the interatomi...

A joint simulation method based on the wave packet molecular dynamics and density functional theory (WPMD-DFT) is applied to study warm dense deuterium (nonideal deuterium plasmas). This method was developed recently as an extension of the wave packet molecular dynamics (WPMD) in which the equations of motion are solved simultaneously for classical...

A method for calculation of the thermodynamic properties of diatomic ideal gases using interatomic interaction potentials is discussed. For instance the computation of thermodynamic functions such as heat capacity, entropy and reduced Gibbs energy in the temperature range 298.15–10 000 K is shown for diatomic argon compounds.

We report on development of the wave packet molecular dynamics (WPMD) with density functional theory (DFT) simulation technique that we proposed earlier for nonideal plasma and warm dense matter simulations. The method is based on the WPMD where the electron exchange-correlation effects are taken into account using the DFT approach. It is aimed at...

The review summarizes the results of the long-term work carried out at the Glushko Thermocenter for the creation of topical databases and the use of new information technologies ensuring the integration of diversified electronic resources. The basic principles of the IVTANTHERMO thermodynamic database and the latest results on the expansion of its...

This paper is a preface to the proceedings of the XV Russian Conference (with international participation) on Thermophysical Properties of Substances (RCTP-15), which was held in Moscow, Russia, October 15–19, 2018.

An analysis of the enthalpy increment and heat capacity data measurements is required for developing thermodynamic databases such as the IVTANTHERMO database created in the Glushko Thermocenter of JIHT RAS. A new CondensedThermoFit code is developed which provides experts with a comprehensive set of analysis tools for working with data on the speci...

The authors calculate the rovibronic partition functions and thermodynamic functions of ArH⁺ and ArH within the temperature range of 298.15–7000 K based on an analysis of their interatomic interaction potential. The calculation results have been added to the IVTANTHERMO Database.

A new wave packet molecular dynamics–density functional theory (WPMD‐DFT) method is proposed for atomistic simulations of non‐ideal plasma and warm dense matter. The method is based on the WPMD approach, where the electronic exchange and correlation effects are treated using an additional energy term taken from DFT. This term is calculated by integ...

Using interatomic interaction potentials for \({\rm{Ar}}_2^+\) and Ar2 molecules, the rovibronic partition functions and thermodynamic functions are calculated for the temperature range of 298.15–10000 K. Different models of the interatomic interaction are compared. The calculation results are added to the IVTANTHERMO Database.

In the context of the development of the IVTANTHERMO information and reference system, heat capacity equations have been derived for solid and liquid stoichiometric uranium dioxide in the temperature ranges of 298.15–3130 K and 3130–8000 K, respectively, on the basis of an analysis of experimental data available in the literature. The appearance of...

Nano-plasmas produced, e.g. in clusters after short-pulse laser irradiation, can show collective excitations as derived from the time evolution of fluctuations in thermodynamic equilibrium. Molecular dynamical simulations are performed for various cluster sizes. New data are obtained for the minimum value of the stationary cluster charge. The bi-lo...

The database structure, main features and user interface of an IVTANTHERMO-Online system are reviewed. This system continues the series of the IVTANTHERMO packages developed in JIHT RAS. It includes the database for thermodynamic properties of individual substances and related software for analysis of experimental results, data fitting, calculation...

In this paper, we review the following simulation techniques for studying nonideal electron–ion plasmas: classical molecular dynamics, wave packet molecular dynamics and Monte Carlo and path integral Monte Carlo. As example the hydrogen nonideal plasma is considered for a wide range of densities and temperatures. The results for the thermodynamic p...

Nano-plasmas produced, e.g. in clusters after short-pulse laser irradiation, can show collective excitations as derived from the time evolution of fluctuations in thermodynamic equilibrium. Molecular dynamical simulations are performed for various cluster sizes. New data are obtained for the minimum value of the stationary cluster charge. The bi-lo...

Development of thermodynamic property databases and thermodynamic modeling algorithms require thermodynamic functions of substances presented in a functional form. In this paper we consider substances in the gaseous state only. The most known methods for approximating dependences of the thermodynamic functions on temperature are overviewed. An algo...

The influence of boundary conditions on results of the classical molecular dynamics simulations of nonideal electron-ion plasma is analyzed. A comprehensive study is performed for the convergence of per-particle potential energy and pressure with the number of particles using both the nearest image method (periodic boundaries) and harmonic reflecti...

The positive ions of 3d metal and argon compounds (metal argide ions, MAr⁺) play essential role in the mass spectrometry with argon plasma sources. At the same time their thermodynamical properties are still not sufficiently studied. Rough estimations of the internal partition functions of MAr⁺ have been made by Witte and Houk in order to calculate...

The influence of boundary conditions for the classical and wave packet molecular dynamics (MD) simulations of nonideal electron-ion plasma is studied. We start with the classical MD and perform a comprehensive study of convergence of the per-particle potential energy and pressure with the number of particles using both the nearest image method (per...

In this paper, we review a multiple-wavepacket version of the Antisymmetrized Wave Packet Molecular Dynamics (AWPMD), that may be utilized to increase the accuracy and the performance of this quantum simulation method. The original WPMD method is based on parameterization of the electron wave function by a single Gaussian wave packet. It gives qual...

Spherically bent crystals are widely used in focusing monochromators, spectrometers and other x-ray optical systems. In particular, they are used in focusing spectrometers with spatial resolution, applied in high energy density diagnostics and warm dense matter studies. In this case, plasma parameters are obtained via measurements of relative inten...

The open source C++ class library GridMD for distributed computing is reviewed including its architecture, functionality and use cases. The library is intended to facilitate development of distributed applications that can be run at contemporary supercomputing clusters and standalone servers managed by Grid or cluster task scheduling middleware. Th...

The nanoplasma produced by laser pulses of moderate intensities 10 13 –10 16 W/cm 2 targeted at metal clusters is studied by molecular dynamics (MD) simulations. Whereas a lot of the cluster plasma studies are concerned with the Coulomb explosion of the ion core we focus on the electron dynamics just after cluster ionization. In particular we consi...

Irradiation of nanosized metallic clusters by femtosecond laser pulses of moderate intensities (&${{10}^{12}}{\rm -}{{10}^{14}}\;{\rm W}\;{\rm c}{{{\rm m}}^{-2}}$;) leads to creation of the so-called electron–ion nanoplasma with size-dependent properties. Electron oscillations in such plasma are of interest in view of resonance absorption or probin...

Pressure fluctuations in equilibrium nonideal plasma are investigated by the method of classical molecular dynamics. Examples of plasma parameters at which the pressure-fluctuation distribution function is not normal but can be approximated by the sum of two normal distributions were found. The electron-ion interaction is described by the Coulomb p...

We present a simulat ion platform which serves as an integrated framework for mu ltiscale and mu ltiphysics modeling of Organic Light Emitting Diodes (OLEDs) and their co mponents. The platform is aimed at the designers of OLEDs with various areas of expert ise ranging fro m the fundamental theory to the manufacturing technology. The platform integ...

The wave packet molecular dynamics (WPMD) method provides a variational approximation to the solution of the time-dependent Schrödinger equation. Its application in the field of high-temperature dense plasmas has yielded diverging electron width (spreading), which results in diminishing electron-nuclear interactions. Electron spreading has previous...

The wave packet molecular dynamics (WPMD) method provides a variational approximation to the solution of the time-dependent Schrödinger equation. Its application in the field of high-temperature dense plasmas has yielded diverging electron width (spreading), which results in diminishing electron-nuclear interactions. Electron spreading has previous...

The method of Wave Packet Molecular Dynamics Method (WPMD) is a promising replacement of the classical molecular dynamics for the simulations of many-electron systems including nonideal plasmas. In this contribution we report on a packet splitting technique where an electron is represented by multiple Gaussians, with mixing coefficients playing the...

We are continuing to extend and simplify our understanding of vacuum arcs. We believe that all the breakdown phenomena we see (with and without B fields) can be explained by: 1) fracture due to electrostatic forces at surface crack junctions, 2) the development of a unipolar arc driven by the cavity electric field, and 3) cooling, and cracking of t...

GridMD is a C++ class library intended for constructing simulation applications and running them in distributed environments. The library abstracts away from details of distributed environments, so that almost no knowledge of distributed computing is required from a physicist working with the library. She or he just uses GridMD function calls insid...

We report on simulation technique and benchmarks for molecular dynamics simulations of the relaxation processes in solids and liquids using the graphics processing units (GPUs). The implementation of a many-body potential such as the embedded atom method (EAM) on GPU is discussed. The benchmarks obtained by LAMMPS and HOOMD packages for simple Lenn...

The dynamical response of metallic clusters up to 10(3) atoms is investigated using the restricted molecular dynamics simulations scheme. Exemplarily, a sodium like material is considered. Correlation functions are evaluated to investigate the spatial structure of collective electron excitations and the optical response of laser-excited clusters. I...

This paper describes the surface environment of the dense plasma arcs that damage rf accelerators, tokamaks and other high gradient structures. We simulate the dense, non-ideal plasma sheath near a metallic surface using Molecular Dynamics (MD) to evaluate sheaths in the non-Debye region for high density, low temperature plasmas. We use direct two-...

form only given. The screening in strongly coupled (nonideal) plasmas is studied using the molecular dynamics simulations. The length and settling time of the electric double layer in a plasma-vacuum interface are obtained. Interaction of strong microwave or laser irradiation with metal surfaces leads to ionization and creation of plasmas. In the c...

The dynamical response of metallic clusters up to $10^3$ atoms is investigated using the restricted molecular dynamics simulations scheme. Exemplarily, sodium like material is considered. Correlation functions are evaluated to investigate the spatial structure of collective electron excitations and optical response of laser excited clusters. In par...

A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel and constant values of the plasma electron density and temperature during the x-ray irradiation. It is demonstrated t...

A plasma model for relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel, and constant values of the plasma electron density and temperature during the X-ray irradiation. It is demonstrated...

The time evolution of laser excited small clusters such as Na309 is investigated using a classical MD simulation code. Results for the electron phase space distribution are analyzed. We are interested intime dependent density and temperature profiles. The question of local thermal equilibrium is addressed comparing the simulated profiles with predi...

A plasma model of relaxation of a medium in heavy ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel and constant values of the plasma electron density and temperature during the X‐ray irradiation. It is demonstrated t...

Laser excited small metallic clusters are simulated using classical pseudo potential molecular dynamics simulations. Time-dependent distribution functions are obtained from the electron and ion trajectories in order to investigate plasma properties. The question of local thermodynamic equilibrium is addressed, and size effects are considered. Resul...

The problem of wave packet broadening in the method of wave packet molecular dynamics simulations of electron–ion nonideal plasmas is discussed. It is shown that when using a harmonic restrictive potential for the packet widths, simulation results depend strongly on the constraint parameter. Two new approaches to constraining the packet broadening...

A plasma model of relaxation of a medium in heavy-ion tracks in condensed matter is proposed. The model is based on three assumptions: the Maxwell distribution of plasma electrons, localization of plasma inside the track nanochannel, and constant values of the plasma electron density and temperature during the x-ray irradiation. The model of multip...

The example of a mixture of simple liquids with Lennard-Jones potentials and soft spheres is used for considering the general principles of relaxation of energy in dense media. The processes of relaxation to uniform velocity distribution are studied, and the main stages of relaxation from nonisothermal state are identified. The dependences of chara...

The dielectric function of dense plasmas is treated within a many-particle linear response theory beyond the RPA. In the long-wavelength limit, the dynamical collision frequency can be introduced which is expressed in terms of momentum and force auto-correlation functions (ACF). Analytical expressions for the collision frequency are considered for...

A study was conducted, to construct a plasma model for the relaxation of the medium near a heavy-ion track. The model was based on the solution to the time-dependent equations of the radiative-collisional kinetics. The state of the medium, which was determined by the atomic model was taken as the initial condition to develop the proposed model. It...

A plasma model of relaxation of a medium in heavy-ion tracks in condensed matter has been proposed. The model is based on the solution of time-dependent equations of radiative-collisional kinetics. The state of the medium, which is described in the framework of the classical model of multiple ionization of target atoms by a field of fast multiply c...

The dielectric function of dense plasmas is treated within a many-particle linear response theory beyond the RPA. In the long-wavelength limit, the dynamical collision frequency can be introduced which is expressed in terms of momentum and force auto-correlation functions (ACF). Analytical expressions for the collision frequency are considered for...

A new approach is proposed to generate workflow scenarios of scientific applications such as Molecular Dynamics and Monte-Carlo simulations in a distributed environment. The approach is based on embedding all workflow elements into the source (C++) code of the application as external library (GridMD) function calls. Thus the compiled executable is...

This paper reports on our research into supporting collaborative distributed applications on the Grid. Our case study application, a Virtual Reactor problem solving environment, was built for simulation of industrially important technology of plasma chemical deposition. It incorporates a number of components distributed among different organization...

Without Abstract

An attempt is made to formulate a set of requirements for simulation and modelling of relaxation in dense media. Each requirement is illustrated by examples of numerical simulation of particles with different types of interaction given by soft-sphere, Lennard–Jones, embedded atom method or Coulomb potential. The approaches developed are expected to...

The optical conductivity sigma (omega) for dense Coulomb systems is investigated using molecular dynamics simulations on the basis of pseudopotentials to mimic quantum effects. Starting from linear response theory, the response in the long-wavelength limit k=0 can be expressed by different types of autocorrelation functions (ACF's) such as the curr...

Langmuir waves and particle-particle collisions in an equilibrium two-component plasma consisting of nondegenerate electrons and singly charged ions are studied by molecular dynamics simulation. Dispersion of frequency and damping rate is determined for Langmuir waves. A method is outlined for extending the theory of Langmuir waves developed for id...

In the long-wavelength limit k=0, the response function has been investigated with respect to the external and internal fields which is expressed by the external and internal conductivity, respectively. Molecular dynamics simulations are performed to obtain the current-current correlation function and the dynamical collision frequency which are com...

Approaches to simulation and modeling of relaxation in dense media are developed which would be universal for some classes of relaxation processes. Three examples of relaxation in strongly dissimilar multi-scale systems are considered: equilibration of electrons and ions in a nonisothermal nonideal plasma, lifetime and nucleation of crystals at sup...

In the long-wavelength limit k=0, the response function has been investigated with respect to the external and internal fields which is expressed by the external and internal conductivity, respectively. Molecular dynamics (MD) simulations are performed to obtain the current-current correlation function and the dynamical collision frequency which ar...

Results for the reflection coefficient of shock-compressed dense xenon plasmas at pressures of 1.6-20 GPa and temperatures around 30 000 K using laser beams of wavelengths 1.06 micro m and 0.694 micro m are presented, which indicate metallic behavior at high densities. For the theoretical description of the experiments, a quantum statistical approa...

Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential st...

An approach is developed for computation of the reflectivity from nonideal plasma for probe laser frequencies ω near the plasma frequency ωp. Different factors are taken into account which could violate the conventional Drude dependence of the reflectivity on the ω/ωp ratio. Possible nonequilibrium of experimental nonideal plasma appears to be the...

Results for the reflection coefficient of shock-compressed dense xenon plasmas at pressures of 1.6–20 GPa and temperatures around 30 000 K are interpreted. In addition to former experiments using laser beams with λ = 1.06 µm, measurements at λ = 0.694 µm have been performed recently. Reflectivities typical for metallic systems are found at high den...

Relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics method for nonideal two-component non-degenerate plasmas. Three limiting examples of initial states of strongly nonequilibrium plasma are considered: zero electron velocities, zero ion velocities and zero velocities of both electrons and ions. The initial n...

The relaxation processes from strongly nonequilibrium states are studied by molecular dynamics simulations for strongly coupled plasmas. For three-dimensional relaxation in the momentum phase space two stages of the relaxation were observed: the initial stage with non-Boltzmann dynamics and further relatively slow Boltzmann relaxation. The first st...

Molecular dynamics method (MDM) supplies to the solution of fundamental contradiction between macroscopic irreversibility and microscopic reversibility with data which help to reveal the origin of stochastization in many-particle systems. The relation between dynamic memory time t m , fluctuation of energy dE and K-entropy (Lyapunov exponent) is tr...

Stochastic properties of equilibrium strongly coupled plasmas are investigated by a molecular dynamics method. The Krylov-Kolmogorov entropy K and the dynamical memory time t(m) are calculated both for electrons and ions with mass ratios 10-10(5). Two values of K entropy for ions are discovered corresponding to electron and ion time scales. The dep...

The molecular dynamics method studied the stochastic properties of equilibrium strongly coupled plasmas. The dependence of Krylov-Kolmogorov entropy K on the number of particles, the nonideality parameter and the form of the interaction potential were investigated for both electrons and ions with mass ratios 10-105. The transition from dynamic to s...

K-entropy is calculated for strongly coupled plasmas by a molecular dynamics method for both electrons and ions. Various time intervals are considered. The results are obtained for different initial displacements of particles, nonidealty parameters, the ion-electron mass ratios, ion-electron interaction potential and the number of particles. Two di...

K-entropy is calculated for strongly coupled plasmas by a molecular dynamics method for both electrons and ions. Various time intervals are considered. The results are obtained for different initial displacements of particles, nonidealty parameters, the ion-electron mass ratios, ion-electron interaction potential and the number of particles. Two di...

The Krylov-Kolmogorov entropy (K-entropy) is calculated for electrons and ions in nonideal plasmas by the method of molecular dynamics. Two different time scales are established corresponding to the electron and ion K-entropies.

The method of molecular dynamics (MD) is widely used to study static and dynamic properties of the condensed matter [1]. In particular an ap-proach to study the relaxation of metastable states is developed [2]. These states play essential role in the impulse loading processes such as shock com-pression, laser ablation, etc. Herewith we report on si...